If you're a celebrity complaining about privacy in your relationships, you might want to talk to Big Bang Theory's Kaley Cuoco. She'll probably have some words of wisdom for you, seeing as she kept a two-year relationship with costar Johnny Galecki completely under wraps.

In the October issue of CBS Watch! Magazine, Kaley opens up about dating Johnny, who was her real-life boyfriend while he played her onscreen boyfriend.

"It was such a huge part of my life and no one knew about it," Cuoco tells the mag in an article accompanied by a steamy photo shoot. "It was a wonderful relationship but we never spoke a word about it and never went anywhere together." In case you were wondering where they got their onscreen chemistry, there is your answer.

However, they managed to keep the onscreen fire burning, even after their offscreen flame flickered out.

Their characters, Leonard and Penny, broke up near the end of Big Bang Theory's last season, but Kaley says she and Johnny ended things "before the holidays", almost six months earlier.

Playing boyfriend/girlfriend while getting over a split could've led to some awfully awkward situations, but Kaley claims it wasn't an issue. "When you're dealing with two professionals who have been working since they were both 4—and who kept their lives extremely private—we didn't want anything other than that."

Kaley also revealed that their concern for privacy may also have been the cause of their eventual split. "We were so protective of ourselves and the show and didn't want anything to ruin that. But that also made it sad, too," Kaley confesses. "That's not the kind of relationship I want—I don't want to be hiding."

Big Bang Theory is currently in its fourth season on CBS.

What say you, BBT fans? Did you spot a more-than-friends connection for Kaley and Johnny? Or can we label them as champions of the secret celebrity relationship?